Many drilling systems include bit bodies having one or more cutters, which allow for more aggressive drilling. The cutters and bit body subjected to extreme forces during drilling operations. Accordingly, the cutters must be firmly attached to the bit body.
Cutters are often attached to the bit body by brazing. The existing process for brazing is labor intensive and produces unpredictable results. The existing process requires a pre-heated bit body and three operators. A first operator adds silver to the braze with a torch. A second operator uses a rod to apply force to the cutters to secure its position. A third operator maintains the base temperature of the bit body with a torch. The existing process is a physically and mentally demanding task that exposes operators to intense heat and is very dependent on the skill and performance of each operator. With up to 100 cutters to braze on a bit body, even one bad braze will reduce the performance of the bit.
Additionally, the existing process is conducted in a natural atmosphere, which requires the use of flux to minimize oxidation. The use of flux creates a risk that flux will be encapsulated by the silver, thereby significantly reducing the strength of the braze.
Moreover, the temperature of the bit and cutter is critical for the quality of the braze. Conventional oxyacetylene torches produce core temperatures of 3,000-4,000° C., resulting in significant variations in temperature of the bit body and the cutters. These temperature fluctuations increase the risk of correcting the position of a cutter when the silver is cooling. If cutters are moved during solidification of the silver, the strength of the silver brazing may be reduced significantly.
Accordingly, there is a need for a new method of brazing that both requires less manual labor and produces a more reliable braze.